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2 years ago

Which of the following is true about scientific knowledge?

Physics

1 answer:

Alla [95]2 years ago

6 0

The answer OC. It can be changed only if all scientists approve the change

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How much energy becomes unavailable for work in an isothermal process at 440 k, if the entropy increase is 25 j/k?

just olya [345]

Answer: 11,000 J

Explanation:

In an isothermal process,

$\text{entropy increase} = \frac{\text{amount of energy in heat transfer}}{\text{temperature} }$ (1)

Note that, the energy used in heat transfer is not available for work. So, the amount of energy unavailable for work is equal to the energy used in heat transfer.

To obtain the amount of energy in heat transfer, we multiply both sides of equation (1) by the denominator of the right side of (1) so that

amount of energy in heat transfer = (entropy increase)(temperature)
= (25 J/K)(440 K)
= 11,000 J

Since the amount of energy unavailable for work is equal to the amount of energy in the heat transfer, therefore the amount of energy unavailable for work is 11,000 J.

8 0

3 years ago

Compare the energy consumption of two commonly used items in the household. Calculate the energy used by a 1.40 kW toaster oven,

Nikolay [14]

Explanation:

It is given that,

Power consumed by toaster oven, $P=1.4\ kW$

Time taken, t = 6 minutes = 0.1 hour

Energy used by toaster, $W_{toaster}=P\times t$

$W_{toaster}=1.4\ kW\times 0.1\ h=0.14\ kWh$

Similarly,

Power consumed by toaster oven, $P=11\ W$

Time taken, t = 9 minutes = 0.15 hour

Energy used by toaster, $W_{toaster}=P\times t$

$W_{toaster}=11\ W\times 0.15\ h=1.65\ Wh=0.0016\ kWh$

Hence, this is the required solution.

3 0

2 years ago

Define 1 joule work ?

Nina [5.8K]

Explanation:

Force is applied to lift a body against the force of gravity. Example: If an object is lifted to a certain height (h)

4 0

2 years ago

You whirl a stone in a horizontal circle in such a way that the stone is in uniform circular motion. Which of the following is t

horsena [70]

a. The direction of the stone's velocity changes as it moves around the circle.

b. The magnitude of the stone's velocity does not change.

d. The change in direction of the stone's motion is due to the centripetal force acting on the stone.

Above given are true for the given situation.

<u>Answer:</u> Option A, B and D

<u>Explanation:</u>

Circular motion may be characterized as the moving of an objects along the diameter of the circle or any circular direction. It may be standardized and non-uniform based on whether or not the rate of rotation is unchanged.

The velocity, a vector quantity is constant in a uniform circle motion speed is constant as its direction continues to change. Centripetal force works inward toward the core to counterbalance the centrifugal force from the center moving outward.

4 0

3 years ago

Which of the following is not a step in the inquiry process

padilas [110]

"The process used by scientific investigations is the scientific method. This involves making an observation, stating a question, formulating a hypothesis, conducting an experiment and analyzing the results to form a conclusion. "

I would most likely go with B. but im not 100% sure

8 0

3 years ago